I'm currently doing some work on a presentation about graphene, and have come across numerous articles which claim something along the lines of

It would take an elephant, balanced on a pencil, to break through a sheet of graphene the thickness of Saran Wrap / Cling Film.

My question is, is there any proof / calculations to back up this claim? Every article I come across seems to be very similar and I cannot find the original source which might contain proof, or a link the relevant paper/study

2 Answers
2

We measured the elastic properties and intrinsic breaking strength of
free-standing monolayer graphene membranes by nanoindentation in an
atomic force microscope. The force-displacement behavior is
interpreted within a framework of nonlinear elastic stress-strain
response, and yields second- and third-order elastic stiffnesses of
340 newtons per meter (N m–1) and –690 Nm–1, respectively. The
breaking strength is 42 N m–1 and represents the intrinsic strength of
a defect-free sheet. These quantities correspond to a Young's modulus
of E = 1.0 terapascals, third-order elastic stiffness of D = –2.0
terapascals, and intrinsic strength of σint = 130 gigapascals for bulk
graphite. These experiments establish graphene as the strongest
material ever measured, and show that atomically perfect nanoscale
materials can be mechanically tested to deformations well beyond the
linear regime.

So when Young's modulus of monolayer graphene is around $10^{12} \;\textrm{Pa}$, a back of the napkin estimate suggests that over a surface of $1 \;\textrm{mm}$ graphene can easily withstand $10^6 \;\textrm{N}$, which looks like a nice guess for an elephant several elephants to me :)

So, are you saying that a sheet of one-atom-thick graphene can support 10^6 N? I know that sounds dumb on my part, but I just want to clarify (I was an English major, not a Physics major) :/
–
Thom Blair IIIMay 26 at 17:02

oh no! it appears I'm too late.. so this is a popular claim, and further popularized by Michio Kaku (youtube). Hover, graphene cannot be as thin as cling film. Why? because graphene by definition is an atomically thin substance! It's literally one layer of graphite, which is how it was discovered. Saran wrap is literally a million times thicker than a sheet of graphene. So, what happens if we stack graphene up to this thickness? We're back at graphite, and that thickness of graphite will not sustain the pressure of your foot, let alone an elephant!

Hypothetically, what if graphene was enlarged to a thickness of saran wrap, and was only an atom thick? Well, that's a silly question, because not even nuclear physics allows that possibility.